ACOS Calculator

Divide ad spend by ad-attributed sales to get advertising cost of sales, the inverse of ROAS.

About ACOS Calculator

The advertising cost of sales is the share of sales attributed to ads that ad spend represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small. Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.

Formula

ACOS

ACOS = Ad spend ÷ Sales attributed to ads × 100

Ad spend: The subset being measured
Sales attributed to ads: The full population it is drawn from

Worked example

With the default values below, ACOS Calculator returns ACOS of 25.00%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Ad spendminimum 0: 12,000
Sales attributed to adsminimum 0: 48,000

Results

ACOS: 25.00%
Remaining (whole minus part): 36,000
Equivalent per 1,000: 250.0
One in Every: 4.0

Step by step

1Values used
2ACOS
3ACOS= 25.00
4Remaining (whole minus part)= 36,000
5Equivalent per 1,000= 250.0
6One in Every= 4.0

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is ACOS calculated?

ACOS = Ad spend ÷ Sales attributed to ads × 100 The advertising cost of sales is the share of sales attributed to ads that ad spend represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small.

Why does ACOS matter?

Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.

What values do I need to enter?

This calculator takes 2 inputs: Ad spend, Sales attributed to ads. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.